Circuit breaker



Filed July 11, 1955 2 Sheets-Sheet 1.

7 50;; 3a [0 In if 40 m 46' 0 74 as 12 4.

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Oct. 29, 1935. E. H. TAYLOR 9 2,018,904 CIRCUIT BREAKER FiledJuly 11,19:53- 2 Sheets-She et 2 Patented 29, 1935 UNITED STATES PATENT OFFICEto The Chase -Shawmut Company, Newburyport, Masa, a-corporation ofMassachusetts Application July 11, 1933, Serial No. 679,901

'23 Claim.

This invention relates to switches and circuit breakers of the typeadapted to control light cir- .cuits and the circuits of relativelysmall pow- ,ered apparatus such as motors and the like.

One of the objects of the present invention is an improved form ofcircuit breaker that is operated manually by an actuating handle and ismoved rapidly into open and closed positions independently of acorresponding movement of the handle and also is moved into open circuitposition independently of movement of the handle by an overload current.

The present switch is particularly adapted for gang mounting in anenclosing box and a further 'object of the invention is an improvedconstrue-- tion that lends itself readily to gang mounting and is ofsmall and compact dimensions and wherein the side of one switch in thegang constitutes the cover for the open side of the adjacent switch.

A yet further object is the provision of a circuit breaker of thetypeabove set forth having overload tripping means including a thermostaticmember that constitutes a component part of the movable switch memberand is in circuit between the contact terminals thereof.

Another object of the invention is the provision of an overload-tripcircuit breaker having overload responsive tripping means therefor andan over-center spring for manually operating the switch between open andclosed positions and wherein the over-center spring also constitutes themeans for moving the switch into open circuit condition when it istripped upon overload.

A further object of the invention is the provision of a circuit breakerhaving a pivotally mounted bridging member and an actuating membertherefor that is pivoted to the bridging member and also is latchedthereto against independent pivotal movement by an overload responsivemechanism, combined with means acting on the actuating member to move itand the bridging member between switch open and closed positions. thebridging mechanism being so arranged that when the actuating member isunlatched from the bridging member it operates through its pivotalconnection therewith to move the bridging member into switch openposition.

Another object of the invention is the provision of an indicating deviceoperated by movements of the aforesaid actuating member to give a visualindication of the electrically tripped condition of the breaker.

A yet further object is generally to improve the construction andoperation of circuit breakers.

Fig. 1 is a plan view of a circuit breaker embodying the presentinvention, the breaker being illustrated in closed position.

Fig. 2 is a view similar to Fig. 1 but with the parts thereof inelectrically tripped open circuit position.

Fig. 3 is a view similar to Fig. 1 but with the parts thereof inmanually operated open circuit position. I

Fig. 4 is a sectional 4-4 of Fig. 1.

Fig. 5 is an exploded view of the operating mechanism.

Fig. 6 is a sectional detail of the guide tube for detail taken alongline 10 the over-center spring guide rod taken along line t-B of Fig. 1.

Fig. 7 is a plan view of the movable bridging member. I

Fig. 8 is a front elevation of a gang of circuit breakers of Fig. 1.

The circuit breaker herein illustrated as embodying the presentinvention has its operative parts enclosedwithin a chamber orcompartment Ill of an enclosing casing I 2, the casing l2 being composedof suitable insulating material having '25 an end wall it which closesone end of the chamber and a peripheral side wall l6 which surrounds thechamber, the other end of the chamber being open. The casing also has abottom wall l8 which is provided with lugs by which the casing can beattached to a suitable support as the back wall 22 of an enclosing boxor housing. The

bottom casing wall l8 also carries stationary contact supports 24 whichterminate within the chamber I 0 in contact members 26. The side walliii of the casing at said contact supports is provided with inturnedsections 28 that are disposed between the contact members and theopenings through which the contact supports pass and function asbarriers or bodies to hinder the discharge of flame when the circuitbreaker opens under an abnormally high current. The side' wall of thecasing has an arcuate front wall 30 which, adjacent the open side of thechamber III, is

recessed to provide a notch 32 through which the operating handle of thebreaker is extended. The breaker mechanism is located within the chamberor compartment lil 'within the open end thereof. When a gang of breakersare mounted together in side by side relation as illustrated in Fig. 8the back wall ll of one casing, overlies and constitutes a cover for theopen chamber of the adjacent casing as illustrated in Fig. 8. 1

The operating handle of the breaker includes an arm 34 which is disposedupon the inner face 66 the Opening in all positions of the operatinghandle. The casing is provided with stoplugs or abutments l8 and 50respectively which define re-' spectively the switch open and closedpositions 0! the operating handle. The movable bridging member comprisesa flat plate 52 that can be composed of either insulating material ormetal and as here shown as being composed of metal. Said plate has a hub54 fixed therein which is journalled upon the spacing sleeve 36 of therivet Ill. Said plate carries a resilient contact supports 56 and 58which as here shown are comprised of flat resilient strips that aredisposed on opposite sides of the supporting plate 52 in generallyparallel relation with said plate and with each other and are terminatedat their free ends in contact members 60 that cooperate with separateones of the stationary contact members 26. The contact supports 56 and58 have refiexed portions 62 that are directed in wardly toward saidsupporting plate 5! and are twisted at right angles to thepiane oi'thecontact' supporting portion of the strips and are fixed to the plate 52by suitable means as rivets i4 and are insulated from said plate 52 bysuitable.

' insulating means as the insulating plates 66. The

contact supports are electrically connected by ag thermal latch platethat is traversed by the' cur rent passing through the, switch and ismovable betweenswitch open and closed positions with the bridgingmember, which includes the supportinfgplatell, and is adapted to operateon excessive currents to eiiect the overload opening 1 oi the switch.The thermal latch comprisesa U-shaped plate of thermostatic material,which can consist of two metals having dissimilar .coeflicients ofthermal expansion secured together back to back. The thermostatic plateis iormed or provided with generally parallel spaced legs 68 that areconnected at their similar ends by thev integral connecting put ormember II, the tree ends of the legs being secured upon the ends 52 ofthe contact supports 56 and I in electrically conducting relationtherebetween by the rivets. The contact supports .and the thermallatch5thus.

constitute in eflect an integral current oonduct 1 ing structure andwiththe supporting' 'plate B comprises the bridging member of thebreaker.

-:The connecting member .100! the thermal latch.

, is provided winieii .ups enqins; detent 12 iii its upper ia'e'e, oriace that'c'onfronts the open '1 end oi'thecompartment jill, the thermalmember is adapted to be reflesed or warped down wardiy when suiiieientiyheated by an abnormal 7 5' current traversing it to effect the opencircuit .movement'of the bridging member.

" 1 The bridging member is provided with en mu ating member thereiorcomprising a plate or arm ll which overlies the head 38 of the rivet ll'and 70 is pivotally connected to the supporting plate-51 by a rivet orother means 18 which is connected with the'piate l! at one sided itspivotai support on the-rivet ll. said actuating member 14" is providedwith a detent II which normally I w sages the detent ll-oi the thermallatch to: mov- .moved into opmcircuit position. -It benotedjhatin 1 ingthe bridging member into closed circuit posi tion and engages aprojection III of the subm tting plate 52 that is spaced back 01' saidthermal latch detent." for moving the bridging member marine ally intocircuit open position. Thus, under the 6 manual operation of thebreaker, the bridging member and actuating member are in eiiect .lockedtogetherv against independent movement. The projection III is spacedfrom the latch detent 12 by a distance substantially greater than thei0} :thickness oi! the detent 18 so that there is a sub-:-

stantial amount of lost play or movement of the detent If in irom theengagement of the l projection into the engagement of the detent" lljThis lost motion is for the purpose of ini5;

suring a positive and rapid action of the bridg ing member between itstwo positions even though .the operating handle is moved very slowly ina corresponding direction, as willbe apparent her-e inaiter. The end ofthe actuating-member ad-SO' iacent the-detent" projects beyond saiddetent "andconstitutes a. stop and is provided with. an I upturned stopmember 82 which when the breaker is tripped electrically comes upagainst an abutment 84 projecting from the end wall ll 01 the 25'casing; When the'breaker is opened and closed manually, .however. saidstop member 82 does not engage the abutment H but is positioned slightlyout of engagement therewith in the closed circuit position of thebreaker as is illustrated in Fig.'1. 80

Said actuating member ll extends in the opposite direction or away fromthe detent ii and .across the pivot rivet III for the actuating memberand has a pivotal connection 85 witha clevis 88. Said clevis is fixed toone end of a guide rod ll that IS i'szi'reelyaxially movable in aguidetube it, see especially Fig. 6, loosely disposed in an aperture -02of the upturned end 42 01 the operating ll'm' 34 for pivotal movementthereon. An over-center.

compression spring ll encircles said guide Zrod 4o andtube and has its.e'nds bearing against the clevi; l6 and against outstanding flange 96of said gnidetube thereby exerting a substantial pressure uponsaid'aetuatlng member II and the handle tending when the switch isclosed-"to hold-the a bridgin and handle incorresponding switchclosedpositions, and, switch is open. tohoid the partsinswitchopenposition 7 to-move the rapidly iromoneto the positionwhen-the-handlels Ill moved milloiently'toward its tio'n the" breaker isopen it--islciosed" b! the: operating; handleim its switchopen positionaufltlehtly toward'itnswitch-closed to move over the l thr h thepivot-.llorthe elem" and. the pivot. oi the movable switch memmovementcauses the spring-to exert apreasurejonihe actuating member to rotate itabout its own pivot Ii andiree the bridsins Ii memberin'acounterclockwise see Fig. 3,, until the ldetent 'll'has passedhomengagement j .with the rig-plate I andinto-engacetnent with the detentHot thebridgins byea mguiegirinnuriner mm eeniiiieiy aflhespring'continnestoact tnthe same with cream the andtthe. bridgingmember to causethe brids'lnsmember to moveiinto-circuitc e ms n o me tthe operatins n needles in the reverse operation oration takes place andthe mementommune a member I is latched to the bridging member so thatboth, in effect. move as one unit between switch open and closedpositions and the actuating member is not free for independent pivotalmovement in any manner that effects a switching operation. when.however, an overload current traverses the closed switch and heats thethermal latch suiiiciently to cause it to warp downwardly to detachthe'detent 12 from engagement with the detent the actuating member isthen free for independent movement about its pivot II. The over-centerspring urges the actuating member for rotation in a counterclockwisedirection, Fig.

,1, which movement brings the abutment member 82 thereof against thefixed abutment 04 of the casing. The engagement of the abutmentsprevents further rotation of the actuating member in this manner. Theover-center spring, however, still exerts pressure on its end of theactuating member and thereby tends to cause it to rock or fulcrum on thefixed abutment 04. This action causes the actuating member to act as alever on its pivot 10 and hence causes the bridging member to rotate ina clockwisedirection about its pivot 00 into an open circuit position asillustrated in Fig. 2, the open circuit position being defined by anabutment 90 of the casing which is engaged by the edge of the supportingmember 02. Thus the freeing of the actuating. member from its latchedconnection with the bridging member and its movement against and aboutthe fulcrum 04 shifts the appiicationof force of the overcenter springfrom one side to the other of the center of the pivot 00 for thebridging member and hence causes the spring to eflect the openingmovement of the bridging member without, however, any physical movementof the spring across the center. The actuating member is reiatched tothe bridging member by a. movement of the operating handle into opencircuit position in which position the force of the over-center springrotates the actuating member in a clockwise direction. restoring thedetent 10 into position behind the detent I! of the latch member of thebridging member. The mechanism thus arranged is simple in constructionand is positive and certain in its operation.

It will be noted that the pressure between the detents l2 and 10 isexerted mainly in the plane of the thermal latch or at right angles tothe warping thereof so that there is little opposition to the warpingand the thermal member thus can be sensitive to overloads.

Mechanism is provided for giving a visual indication of the electricallytripped condition of the breaker. Said mechanism includes an indicatingsegment or target I00 which is pivoted on a pin I02 carried by theoperating handle and disposed in a slot I04 of one of the arcuate arms46 of the handle so that its arcuate surface is disposed in a positionto be visible when the handle is in -circuit closed position. Thesegment bears a suitable indicating mark, which can be a color, on aportion I06 of its surface that,

when the breaker is in manually opened or closed condition, is concealedbehind a portion of the arcuate arm 40 but is adapted to be exposed whenthe breaker is tripped electrically. The segment I00 is connectedthrough a tensile spring I08 with the actuating member I4 at a suitablepoint intermediate its pivotal point and its pivotal connection 00 withthe clevis 06 and preferably over v the axis of the pivot 40. When thebreaker is 1 manually opened and closed the tensile spring I 00 isalways under such tension as to keep the axis of the spring in line withthe pivot I02 of the segment and the pivot 40. When, however, theactuating member is tripped and moves into a position to effect theelectrically tripped opening I of the breaker the line of pull of thespring I00 is shifted in such direction as to cause the segment I00 tobe rotated sumciently to expose the marked portion I00 thereof andthereby to indi-' cate visually that 'the switch has been opened 10electrically. Thus theshifting of the position of the actuating memberwhen electrically tripped is caused to indicate the tripped condition ofthe breaker. a

I claim:

1. A circuit breaker comprising cooperating stationary and movablecontact members, and actuating mechanism for the movable contact memberhaving a latch connection therewith and an over-center spring urgingsaid movable'contact member in .one direction when latched to saidactuating mechanism and in the opposite direction when unlatchedtherefrom.

2. A circuit breaker comprising cooperating stationary and movablecontact members, actuating mechanism for the movable contact memberhaving a breakable connection therewith and an over-center spring urgingsaid movable contact member in one direction when connected to saidactuating mechanism and in the opposite direction when disconnectedtherefrom. and overload responsive means controlling said breakableconnection.

3. A circuit breaker comprising cooperating stationary and movablecontact members, operating mechanism for said movable contact membercomprising an actuating member having a latch connection with saidmovable contact member, and an over-center spring acting in one positionthereof on said actuating member to move 49 said movable contact memberin a circuit closing direction and acting through said unlatchedactuating member to move said movable contact member'in a circuitopening direction.

4. A circuit breaker comprising a pivotally mounted contact member, anactuating member therefor having a pivotal and also a latch connectionwith said movable contact member, and an over-center spring acting onsaid actuating member tomoveit and said movablecontactmemher from aswitch open to a switch closed position and from a switch closedposition to a switch open position and when said actuating member isunlatched to move said movable switch member from switch closed toswitch open position.

5. A circuit breaker comprising a pivoted switch member, an actuatingmember therefor having a pivotal connection with said switch member, anda latch connection therewith which normally holds said actuating memberagainst operative movement about its pivot, means including anover-center spring acting on said actuating member to move it and saidswitch member between open and closed positions, and means providing afulcrum engageable with said unlatched actuating member to change thepoint of eil'ective application of the force of said spring on saidswitch member to move it into an open circuit position.

6. A circuit breaker comprising a pivoted switch member, means includingan over-center spring to move said switch member between open and switchmember from one side to the other otthe pivot thereof for effecting theopening movement of said switch member.

7. A circuit breaker comprising a pivoted switch member, an actuatingmember having a pivotal and also a latch connection with said movableswitch member, an over-center spring acting on said actuating member onthe side of the pivot 01 said pivoted switch member opposite its pivotalconnection with said actuating member, and a fulcrum against which theunlatched actmting member is pressed by said spring to move said switchmember in a circuit controlling direction.

8. A circuit breaker comprising a pivoted switch member, an actuatingmember having a pivotal and also a latch connection with said movableswitch member, an over-center spring acting on said actuating member onthe side of the pivot of said pivoted switch member opposite its pivotalconnection with said actuating member, and a fulcrum against which the'unlatched actuating member is pressed by said spring to move saidswitch member in a circuit controlling direction and means for movingsaid over-center spring over center. v

9. A circuit breaker comprising a pivoted .switch member, an actuatingmember therefor having a pivotal connection therewith atone side '01 the,switch closed and open positions.

pivotal center of said movable switch member and also having a latchconnection therewith so arranged that said actuating and switch membersare constrained for pivotal movement as a unit about the pivot of saidpivotal switch member, an over-center spring acting on said actuatingmember on the other side of the pivot of said switch member, means formoving said spring over-center to move the switch member between switchopen and closed pomtions, and ai'ulcrum I disposed in position tobe'engaged by said imlatched actuating member to effect the opencir cultmovement of said movable switch member.

'10. A circuit breaker comprising 'a pivoted switch member movablebetween open and closed positions, a pivoted actuatingmember ior saidswitch member having a lost motion connection therewith, and anover-center spring act-,

ing on said actuating member tomove it'and said movable switch memberbetween switch open and closed positions and to move said actuatingmember from one end to the other of its lost motion connection at thetime said over-center'spring passes over center. v f

11. A circuit breaker comprising is pivoted switch member having a pairof spaced abutments, 9. pivoted actuating member for said movable switchmember having a detent that is posil iioned loosely between saidabutments, and an mal latch carried by said plate and constitutingover-center spring acting on said actuating member to move it and saidswitch member between switch open and closed positions, said abutmentsand detents being so that said vdetent I between it and said actuatingmember, means' passes from the engagement of one abutment to. that ofthe other during the movement of said spring over center. v

'12. A circuit breaker comprising a movable switch member including apivoted supportingplate, contact members carried thereby. a thertheelectrical connection betweensaid contact members, an actuating memberfor said movable switch member having a normally latched engagement withsaid thermal latch, and an overcenter spring acting on said actuatingmember for moving said movable switch member when aoiasos latched intoswitch closed position and when urilatched into switch open position.

13. A circuit breaker comprising a pivoted switch member, an actuatingmember therefor" having a latch connection with said switch memg ber,means including an over-center spring for moving said actuating andswitch members between switch open and closed positions, and thermalmeans carried by said switch memberior breaking said latch connectionand eiifecting the in circuit opening movement of said movable switchmember by said over-center spring.

14. A circuit breaker comprising a pivoted switch member including athermostatic plate fixed to saidswitch member at one end and tree 15 towarp at the other end, contact members carried by said movable switchmember and connected electrically in series with said thermostaticplate, an actuating member pivoted to said movable switch member andalso having a latch con- 20. nection therewith through said thermostaticplate which normally restrains said actuating member from operativemovement about its pivot, and means including an over-center spring formoving said actuating member and switch. member 25 conjointly betweenswitch open and closed positions and said'unlatched switch memberindependently of said actuating member between switch member oppositethe pivot of said actuating member, means for moving said'over-center 0-spring over-center to move said actuating. and switeh members conjointlybetween open and ,closed circuit-positions, and means providingwa'fulcrum for said unlatched actuating member dis-' posed 'to cause saidover-center spring to act is through the pivot of said actuating memberwith 'saidymovable' switch member to move the latter from closed circuitto open circuit'position.

18. A circuit breaker comprising a movable 1 switch member including apivoted plate, contact 60 members carried by said plate, a U-shapedthermostatic platehaving its legs fixed to said plate and connectedelectrically between said contact member, an actuating member overlyingsaid movable switch member and having a pivotal con- 55 nectiontherewith at one side of the pivot of said switch member and also havinga latch connection therewith controlled by said thermostatic plate, anover-center spring acting on saidactuating member on the side. of thepivot of said switch member opposite the pivotal connection movement oisaid-'movablejswltch' member;

17. In aclrcuit" breaker: comprising a switch member movable betweenswitch open and closed 9 positions, and-indicating. means movable. from-.'a switchclosed position into a position which indicates theelectrically opened condition oi the switch, the combination therewithvoi an' actuating member movableconiointly with n switch 15 memberbetween open and closed positions and movable independently of saidmovable switch member when said switch member is electrically actuatedfor circuit opening movement, and means connecting said indicating meansand said actuating member operative upon such independent movement ofsaid actuating member to effect movement of said indicating member intoits position which indicates the electrically opened ing member formoving it between switch open and closed positions, overload responsivemeans for eil'ecting the overload opening of the switch, the combinationtherewith of an arrangement wherein said connection is breakable andsaid spring is operative when said connection is broken to effectindependent movement of said actuating and movable switch members; saidindicator being carried by said handle and being responsive to movementof said independent movement 01 said actuating member to be movedthereby into a position indicating the overload responsive movement ofsaid. movable switch member.

19. In a'circuit breaker comprising a pivoted switch member, anactuating member therefor, an operating handle, an over-center springconnecting said handle and said actuating member for moving it and saidmovable switch member conjointly between open and closed circuitpositions, overload responsive means for eiiecting movement of saidmovable switch member into open circuit position, the combinationtherewith of a pivotal and also a latch connection between saidactuating and switch members, said overload responsive means beingarranged to break said latch connection, said spring being thereuponarranged to efl'eet movement of said actuating member about its ownpivot, a pivoted open circuit indieating member, a tensile springconnected with said indicating member and also with said actuatingmember about in line with .the pivot of said pivoted switch member, saidactuating member in its independent movement thereof moving away fromthe pivot 01' said switch member and hence effecting the pivotalmovement of said indicating member.

20. A circuit breaker as defined in claim 19 wherein said operatinghandle and said pivoted switch member are concentrically pivoted andwherein said pivoted indicating member is car-- ried by said handle.

21. A circuit breaker comprising a pivotedswitch member, an actuatingarm for said switch member having a pivotal bearing thereon, a lockbetween said switch member and actuating arm, tripping means for saidlock, a fulcrum engaged by said unlocked arm, and an over-center springact-ing on said arm, the points of engagement of said arm with saidspring and fulcrum being so positioned with respect to the location ofsaid pivotal bearing between said arm and switch member that said springacting through said latched arm urges said movable switch member in onedirection and acting through said unlatehed arm urges said movableswitch member in the opposite direction.

22. A circuit breaker comprising a pivoted switch member, an actuatingarm pivoted to said switch member eccentrically of the pivot thereof, alatch connection between said actuating arm and switch member, a fulcrumfor said unlatehed actuating arm, and an over-center spring acting onsaid actuating arm.

23. An electric switch comprising a movable contact member, an armmovable in opposite directions for moving said contact member betweenopen and closed positions, means providing two xfulerums for said arm, aspring acting in the ELMER H. TAYLOR.

